[ML] [Meta] Spaces follow up tasks

[jgowdyelastic]

Tasks carried over from #82415

These tasks focus on how space aware ML features interact with the rest of kibana and other plugins.

• Update kibana capabilities to include license checks on initialisation.
  • re-enable jobsSummary and mlAnomalySearch security checks, which were disabled due to alerting limitations (Users in the alerting context  #64588)
• Change all integrated plugins so they are using our functions or endpoints
  • All endpoint calls are replaced with calls to a shared function. This is lower priority as privilege and space checks will be built into our endpoints, so calling them will not allow circumvention of security or spaces. However, for NP completeness, other plugins should not really be calling our kibana endpoints.
• Rely on Kibana privileges to control access to ML functionality
  • Add ML links to Home page sample data sets depending on kibana capabilities

[elasticmachine]

Pinging @elastic/ml-ui (:ml)